freeman



(No Model.)

' W. P. FREEMAN.

' GOMMUTATOR EOE DYNAMO ELECTRIC MACHINES.

No. 313,489. v Patented Mar. 10,1885.

WITNESSES LNVEJV'TOR y /ZM W Attorney UNITED STATES PATENT OFFICE.

WARREN P. FREEMAN, OF NEWV YORK, N. Y.

COMMUTATOR FOR DYNAMO-ELECTRIC MACHINES.

SPECIFICATION forming part of Letters Patent N0. 313,489, dated March 10, 1885.

Application filed March 10, 1884.

T0 (LZZ whom it may concern.-

Be it known that I, WARREN P. FREE- MAN, of the city, county, and State of New York, have invented a new and useful Improvement in Oommutators for Dynamo- Electric Machines; and I hereby declare the following to be a full and clear description thereof.

This invention relates to an improved con struction of the cylindrical drum or body of the commutator, and the arrangement on and attachment of the comnnitator-strips thereto, and will be readily understood by the accompanying drawings, of which Figure 1 is a sectional elevation of the improved commutator, taken on the line 00 a" of Fig. 3. Fig. 2 is an end elevation of the commutator. Fig. 3 is a sectional plan ofit, taken on the line y y of Fig. 1. Figs. 4 and 5 are respectively a sectional elevation of the bushing for insulating the screw and the screw used for attaching the commutatorstrips to the cylindrical drum.

The central or body part of the commutator consists of a drum or cylinder, A, which has a hub, a, through which its driving shaft passes, and an annular flange, a, at each side of it at the periphery.

The commutator-strips B are placed transversely on the outside or periphery of the cylinder A, and secured thereto by means of screws 0, passing through the flanges a, and threaded in the said commutator strips. Each of the said screws in passing through the flange a is surrounded by an insulatingbushing. D, made of some suitable insulating 1naterialsuch as hard rubber, for instance. Each of the said bushing-pieces has a flange at its inner end, as shown clearly in Fig. 4, the said flange resting against the inner face of the flange a of the drum when the parts are assembled, as shown in the other figures of the drawings. An annular strip or sheet, E, of hard rubber or other insulating material, is interposed between the periphery of the drum A and the surrounding commutator-strips B, and an insulating-strip, F, of a like material, is interposed between each two adjacent edges of the commutator-strips. By means of these insulators and the screwbushings D the commutator-strips are perfectly insulated, and the said commutatorstrips are held firmly to the periphery of the (N0 model.)

drum A by means of the screws 0, one screw in each end of each commutator-strip. The said screws being threaded in the pieces B, and placed radially through the flanges a, with the heads of the screws placed inwardly toward the hub of the commutator, the parts are held firmly together without any liability to displacement of the commutator-strips or the production of cross currents resulting therefrom. The heads of the screws 0 being placed inwardly toward the hub of the commutator, there are no perforations or obstructions on the outsides of the commutatorstrips, the holes for the said screws not etc tending through the said strips; consequently there are no peripheral impediments to the continuous and perfect action of the ma chine.

In one end of each of the comn'iutator-strips B there is inserted a metallic screw, G, with a washer, H, under its head, for the attachment of the wires leading from the dynamo through the dynamo-shaft in a manner well known.

Having described my invention, I claim 1. A commutator for a dynamo-electric machine, having the commutator-strips placed transversely 011 the periphery of the commutator drum or cylinder, and secured thereto by means of retainingscrews passing radially through peripheral flanges at the sides of the said drum, the screws threaded in the said commutator strips, and placed with their heads toward the hub of the said drum or cylinder.

2. A commutator for a dynamo electric machine, consisting of a drum or cylinder, A, peripheral commutator strips B, secured thereto by insulated screws 0, passing radially outward through side flanges, a, at the periphery of the drum or cylinder A, and

threaded in the said commutator-strips, and

insulating strips E and F, respectively separating the commutator-strips from the drum or cylinder and from each other.

In testimony whereof I have signed my name to this specification in presence of two subscribing witnesses.

XVARREN P. FREEMAN.

\Vitnesses:

M. RANDOLPH, W. J. DOUGHTY.

IOCl 

